Is there absolutely now way you can imagine you two surviving a polyamorous relationship? Think of a fantasy la-la-land where you both fall for this awesome bi guy whose super-attractive, mature and totally into you both? Is this a horrible future scenario where you would be equally miserable than in any other possible non-monogamous future you can imagine?

Well, in that scenario yes. However I am not sure that I would want to be with someone who my wife would be with. But in that fantasy land, I could see something like that working.